Land Crayfish - Who's digging in my lawn?

Residents of south-eastern Australia, especially of the Dandenong Ranges near Melbourne, may find round holes appearing on their lawns. Sometimes if left alone high chimneys of soil grow up from the holes. These structures are the work of land crayfish.

Who digs the burrows?

Land crayfish (sometimes called “land crabs” although they are not crabs) are relatives of yabbies, Murray crayfish and, more distantly, marine scampi. This group of Crustacea, the Astacidea, is recognised by the possession of a pair of equal large claws and two other pairs of smaller nippers. That is, three of the five pairs of legs are chelate.

The family Parastacidae, to which yabbies and land crayfish belong, is found only on southern continents but is most diverse in Australia. Land crayfish are one of 34 species in the genus Engaeus. Many of these species have a quite limited geographic range and some confined only to a single catchment.

Species of Engaeus are smaller than the more familiar and edible yabbies (Cherax destructor) and only grow to a maximum length of 120 mm. The carapace is more flattened from side to side than in a yabby and the abdomen (tail) is smaller and often bristly. So small in fact that they are inedible.

What is under the openings of the burrows?

Land crayfish live only in damp environments which is why the hilly regions of eastern Victoria and Tasmania are home to most species. Here, they are found in swamps, near streams, eucalypt forests or rainforests. Their subterranean homes vary according to species and depend on their habitat.

Some species, such as Engaeus urostrictus, live close to streams. Here they build burrows down to 25 cm deep at the level of the water table. Water fills a small chamber at the bottom of the branching burrowing system covering half a square metre. As the crayfish excavates the burrow it brings soil to the surface and places the pellets around the entrance until a chimney grows up to 13 cm high.

Other species, Engaeus tuberculatus for example, live on slopes away from streams. Their burrows do not reach the water table and the subterranean chambers rely on rain or seepage to fill with water. Exit burrows diverge near the surface where there are several openings. Waste from the excavations is brought to the surface where pellets of soil are deposited and run down the slope to form a fan of dirt.

What are the crayfish doing down there?

The crayfish spends most of its time in the chamber at the bottom of its burrow so is rarely seen. Only at night does it become active bringing soil to the surface. It feeds mostly on decaying roots and buried plant matter, but sometimes eats worms or insects. Some species live alone but others are more communal.

Male and females usually come together to mate in spring and eggs are incubated attached to the tail of the female. Juveniles hatch in mid–late summer. After hatching they may remain in their parents’ burrow or migrate to start a life of their own.

Besides the crayfish is a very specialised fauna of aquatic crustaceans and insects, some not found in other watery habitats.

Conservation

Because the burrowing crayfish’s habitat is threatened by land clearing and drainage, the species themselves are thought to be threatened.

Comments (72)

we just moved to hervey bay on 5 acres we have a dam out the front. the previous owners said they put red claw in the dam be we have found oceans of holes all over the property and none in the dam. we took a picture of some we dug up.do red claw burrow too?

Hi Vicki, according to information on the NSW Department of Primary Agriculture website, the Redclaw are omnivorous with a diet that includes small invertebrates and aquatic plants. In their natural habitat, redclaw are a relatively non-aggressive, non-burrowing species. However, observation of introduced populations and within the aquarium trade, indicate that this species can display aggressiveness and burrowing habits.

cheryl
18 February, 2015 11:52

Julia, i too have a couple of small holesright next to the base of a tree. which i have been nuturing through the really hot and cold months, only to find that it's not looking too good at the moment. I did find some cane beatles in holes that were next to my bottlebrush trees. What to put in these holes is a dillema, as you don't want to hurt the roots of your trees.

I live in Mitcham and have found them in my yard. I have photographed many that have been dug up during building works. I have put in a new drainage system to get rid of surface water but I have noticed a couple of new holes in the garden beds. I am worried the tunnels will undermine the footings - should I be concerned?

We live in the Dandenongs and have always had a few of these of these around the place.
Lately they have got into my lawn and made a real mess.
Literally hundreds of holes in my lawn and big piles of mud everywhere.
After a lot of research I've found Bifenthrin will do the trick.
It is usually used for termite treatment so will stay in the soil, killing spiders, bugs, termites and of course crayfish.
Masters sell David Grays Bifenthrin. (Bunnings don't sell it).
I mixed it to termite strength as per instructions and sprayed it down every hole. All gone :).
I only treated the ones in my lawn, not in flower beds etc. Happy to live and let live as long as not destroying my lawn!

We have bought a property in the suburb of Upwey, the bottom of which is quite wet all year round and has plenty of the Yabby holes and sometimes Chimneys. They are the Engaeus urostrictus, Dandenong Burrowing Crayfish. I have read that they are an endangered species, are they protected, and if so where can i obtain the legislation?

Hi Alan, Engaeus urostrictus is unlikely to be the species you are observing as they tend to have burrows at the edge of streams. It is more likely to be E. victoriensis (Endangered), E. cunicularius or E. tuberculatus (Endangered).
E. urostrictus does not currently have an action statement.

Discovery Centre
17 July, 2014 14:42

Hi Alan, the Dandenong Burrowing Crayfish, Engaeus urostrictus is listed under Victoria's Flora and Fauna Guarantee Act. The best thing would be to contact the Department of Environment and Primary Industries to check what the current stauts of this invertebrate is and whether it has a management plan.

Jeff
6 July, 2014 11:29

Kentucky here. Crayfish made castles all over my lawn. Had me puzzled, as I am from Utah and I never encountered them there. I guess various species of burrowing "mud bugs" live world-wide.

who would have thought.. land yabbies??!! I work in a vineyard in northen Tassie, i've found heaps of holes and wondered what made them. Can they do damage to the root systems of plants? the holes are pretty close to the vines. A pretty sweet sounding little creature until I read about the foundation damage, on here. Long live the land yabbie anyway! cheers, Courtney

Hi Courtney, we're not aware of these posing any great threat to wineries. A search of the Australian Wine Research Institute turned up only one reference to yabby which featured in the name of one of the wineries.

Don Goodson
3 June, 2014 23:46

We live in benton, ark our home sets on half acre, big backyard, behind that is a 32 acre lake. after we moved in later that summer there were alot of these dirt chimneys in backyard. when it rain the yard does stay wet for along time before it is dry to cut. would that mean that the yard is moist all the time. The poeple next to us [on both sides] does not have any, maybe their yard is to dry? What can I do to get ride of them?

I live in Mt Evelyn Vic.Two evenings ago while hanging out my washing my lawn collapsed and my foot dissapeared into a 250cm deep cavern created by these little creatures. I managed to aprehend four of the culprits while the rest scurried through a maze of escape routs. Ten years ago I had a hot water service unit plus it's base slab dissapear into the ground in a similar fashion On digging out the labarynth to create a new base for the hot water system I collected about a third of a bucket of these expert tunnelers..Endangered??...NO, thriving in Mt Evelyn. P.S. interrogation of the latest captives has not lead to the capture of the rest of the gang.

Thank you Sophie Peterson. I have also been horrified by the number of people who want to kill these animals because they are an inconvenience to them. I came looking around for info on them because I am fascinated by the way I find the signs of their existence but never see them. I am getting quite a collection of their claws. Are these claws I find a result of those eaten by predators or do they fight with each other? I have also heard clicking noises in the night only to discover a lot of claws the next morning.

Land crayfish are rarely seen during the day due to the fact that they spend most daylight hours in their chambers at the bottom of their burrows. They only become active at night bringing soil to the surface, which probably explains why you never see them!

Regarding the claws you have found crayfish are capable of deliberately discarding a claw for protection which will then gradually be regrown. This could be as a result of an attack from a predator or the fact that, during the breeding season, males have been known to fight for the right to breed. However the more likely explanation for the claws you have found is that crayfish, like all arthropods, shed or moult their outer skin every three to four weeks in order to grow. It is common for the crayfish to lose a claw during this shedding process which will then be regrown.

Vannessa
9 October, 2013 10:22

I just found what could be a land yabbie thing in my backyard. It was on the surface of the lawn and dead. I've now got it in a jar. I haven't noticed any mounds in my lawn but the grass is quite overgrown at the moment. I had no idea what it was until I asked on Facebook. I've never seen anything like it!

I got some of these land crayfish that lives on the slopes and they seem to only get water from the rain as they live nowhere close to a pond or stream. My question is, Can I keep them as pets?
( Oh, and if I remember it right. The food tied to a string strategy you were saying, it works for me, I use meat and I actually got to see it come out, not all the way. Plus I also had a chance to see them build their chimney. It didn't seem to be afraid of me watching it build it? )

After reading your very informative article I am still confused about what is burrowing in my back yard. At present the soil is very wet and I just noticed at least 40 or 50 of these little holes about the size of an American dime, or slightly smaller than a 5 cent coin. They're on the wettest parts of the soil in a couple of places. However, there are no chimneys (as described in the article), just little holes everywhere. My dogs are fond of eating what they dig up in the soil (including any and all bugs), and I am a little concerned about these little beasties nipping the dogs or becoming lodged in their throats. I am also keen to protect an endangered species from my dogs respective appetites. Any info you can pass on about what I'm dealing with would be greatly appreciated. Thank you.
BTW, I am in Rowville Victoria.

Hi Leisha - We passed your enquiry on to our Live Exhibits staff, who gave us the following info, hope it's helpful:

The holes are most likely from land crayfish, in this case probably Engaeus victoriensis. They don't always build chimneys, particularly when the soil and subsoil are very wet. They look like smaller versions of the common yabby and are generally harmless, so they are unlikely to cause any problems to your dogs, even if swallowed. Land crayfish are rarely seen on the surface so your dogs will not generally come in contact with them unless they are dug up. Although it's good to take measures to protect native wildlife from domestic pets, this species is common and their presence in your yard may be only transient until the soil begins to dry.

Sophie Peterson
10 April, 2013 09:39

Its a shame to realize that people in Australia are as clueless and selfish as folks in the States. These animals are threatened because of the development of their habitat into your backyard. Just because there are "hundreds" in your neighborhood does not mean the species is fairing well as a whole. Historically, there were probably MILLIONS in your area before your housing development went up. YOu can't eat them, you can't kill them, you have to learn to live with them. Otherwise, move somewhere where the crayfish don't live. I am so tired of people like you.

Hi I've just moved into a suburban property in Moe, the holes and mounds I'm seeing are huge compared to what you've described. Some are large enough for my young boys to stick their hands down, which is quite worrying when they're playing in the backyard unsupervised. I just received a letter saying I have a sewage maintenance hole located somewhere in my yard, could that be whats attracting them to my yard? I've asked neighbours and friends who live a couple of hundred metres away and they have none in their yard or on their lawns. Why just where I live?

I have lived and farmed in Lennon, Michigan all my life. I always thought these "mud chimneys" we're snake holes. Recently, I went to the Chippewa Nature Center in Midland & learned @ crayfish & their burrows. We see them everywhere up here where there is moist ground or standing water. I have never seen a crayfish but now I will be looking for them . How do they survive the cold winters up here. Like frogs I guess?

Hi Alicia - we referred this to our Live Exhibits Department, who have provided the following response for you:

The crayfish known as a 'yabby' lives in open freshwater bodies (Cherax destructor). What you have in your garden sounds like 'burrowing crayfish', probably in the genus Engaeus.

As their name suggests, they burrow into soil and live in tunnel systems where they feed on organic matter from the soil. They require water to breathe but will also leave the tunnel at night or in damp and heavily overcast weather.

Given their combined aquatic/terrestrial lifestyle and their specialised feeding techniques, it's best not to attempt to keep them in captivity.

Several species of burrowing crayfish are also threatened and are protected by law, so cannot be collected.

Sjay
9 October, 2012 15:51

I live in Healesville, Vic on 2 acres and it simply would not ve possible to count the thousands of holes around the property. Strangley enough though never seen one a few friends have fallen through holes though.

I have a tiny little trickle of a creek at the edge of my yard and down a 20 foot hill. In my yard at least 75 feet from the creek I find these crayfish" burrowed into the ground. In southwest Ohio with heavy clay and up on a hill I can't imagine why they are here. My dog dug one up once and it was probably 12+ inches long! WOW!

Is the land yabbie also considered a threatened species? If so please come and get them out of my backyard. I have a tiny backyard in Ringwood East Vic and have approximately 50 holes. Found two in my fish pond at different times and one of those times a fish (approximately 100cm long) with its side slashed floating on top, the yabbie was still alive at the bottom of the pond. They are wrecking my little garden. I sometimes find some of the smaller plants fallen over. Am at my wits end as to how to stop this. I only water once or twice a week, so its not like the garden is saturated. HELP!!!

Hi June, The Victorian Department of Primary Industries Fisheries page on Freshwater Fish of Victoria: Yabbies at provides information on burrowing freshwater yabbies. Freshwater yabbies (Engaeus species) excavate extensive burrows in damp and wet soils and these are connected to the water table. This can cause water-logging of tree roots and undermine building foundations. This water-logging will be causing your trees to die. Part of their diet is rotting wood, detritus and root material which will further damage your trees.

Well we here in Southern Louisiana in the USA have them all over. As a matter if fact we have crawfish farms and raise them. They are a main course of food for outside activities in the spring and summer. We call it a crawfish boil. We get about 5 lbs per person (about 20-40 lb sacks of them) and boil them. We add spices, corn on the cob, potatoes, mushrooms, whole onions, and just about any other vegie is good added into the pot when we boil them. It is a multi million dollar business down south in this Cajun Country.

Hi Julia, There are a number of animals that create holes in the ground. Museum Victoria has a free Identification Service. If you would like to send us a photo of the holes, we'd be very happy to identify them for you.

We have moved into a house on the gold coast and have just started noticing holes in our yard. They don't have mounds like described on previous posts but are perfect little holes about the size of a 10 cent piece. Would this be the yabbies or should I be worried about termites or something? Thanks

We live in the Macclesfield-Avonsleigh area of the Dandenong Ranges and we have seen small crayfish sized "yabbies" with blue pincers in the vicinity of a spring. We are intrigued as to what species this is, and whether they are endangered.

Moved up to the Belgrave area about a year ago and encountered a couple of these crayfish. Also found dozens of holes on my property, which I didn't know whether they were related to the crays or were some sort of termite mound (we have plenty of them around too). Information on and images of earth mounds just returns a heap of Northern Territory images - Thank goodness for this site.
Like Rudi mentioned above, one of the crays had black worm like things attached to its legs. I'm no expert, but looked like leeches to me. What benefit they get out of a critter like this is beyond me.

we also have them everywhere, it is just part of our lives in the area we live
i dug a chamber up once, they are as said a shovel depth or so below the surface with a chamber about half a meter square, half filled with water
i have a good photo of one but do not know how to paste it here, he decided to take a walk up our pathway on a very wet night, in fact one of the wetest nights i have seen

Hi Jennifer, Museum Victoria specialises in natural sciences related to Australia and in particular south-east Australia. We would suggest you contact the Florida Museum of Natural History who will hopefully be able to help you.

Julie, I’m afraid we cannot offer any advice as to how to eradicate a threatened species. The following species are listed as threatened in accordance with Section 10 of the Flora and Fauna Guarantee Act 1988: Curve-tail Burrowing Crayfish (Engaeus curvisuturus), Mallacoota Burrowing Crayfish (Engaeus mallacoota),Narracan Burrowing Crayfish(Engaeus phyllocercus), Strzelecki Burrowing Crayfish (Engaeus rostrogaleatus), Warragul Burrowing Crayfish (Engaeus sternalis) and Dandenong Burrowing Crayfish (Engaeus urostrictus). We would be happy to identify which species you have in your yard and answer any other questions you may have about them.

Hi to all.
I live in Mirboo North and my front yard is inundated with 'yabbie' holes. It's a pest really, because they are digging all over the yard. They also seem to be digging around the house foundations - creating rather large pot/sink holes !
My yard is very damp, in fact one could call it wet (the ferns love it) I am on the low side of the road.
There is no way that these little critters are threatened here - aside from my wanting them gone !
I would like to know how to get rid of them ????
Any advice would be appreciated.
Cheers
Jul

I have had these land crayfish in my yard (Seville East - vic) for many years and are familiar with the chimneys. But a couple of days ago my large dog was up the yard in a hole that was about 1 meter deep, 1.5m long and about half a meter wide. He had obviously had the land sink from under him. there are also some other large holes but not as big as the one mentioned. Someone who lives in the area tells me these crayfish dig down and then burrow tunnels that fill with water and that is why these holes are developing. I am worried for the dog and myself and also because where these holes are appearing is in front of two very large messmate gum trees. Can you please give me any advise?

im down near wilsons prom and there are a few different spieces here in peoples back yards. we ve seen the most common here, which is the small light skin coloured ones, but also a larger one that has blue claws and a darker colour. could you let me know what spieces they both are? i have heard the blue claw is protected, and yes it does live under the ground also. thanx

We live in Gellibrand river Victoria and have many around our house. When it gets very wet in the middle of winter here if you gout with a torch at night you will find them out of their burrows,people around here call them land yabbies.

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Discovery Centre
31 January, 2011 19:05

Hi Rudi, the crayfish you saw wandering around near Noojee would most likely have been a different kind of crayfish to the ones that make the mud chimneys. As to the worms on their legs, we don't currently have an expert in this area but if you see them again and can get an image send it to discoverycentre@museum.vic.gov.au and we will see if we can help.

Was camping at Nojee on top of a hill, there were heaps of these creatures during all daylight hours crawling around... so they are not limited to nocturnal hours.. anyway.. what are the worm like things protruding from there legs....?

Hi Dan, the yabby that you are finding in the dam is likely to be a different species to the ones making the chimneys on your property. It is likely to be one of the larger species of yabby from the genus Cherax.

I live on acerage at Yallourn North. I have noticed hundreds of these burrows all over our property. I decided to throw a few opera house traps in three nearby dams. One yabby in a week. Do these land lovers travel into farm dams?

Today we found a small lobster like animal in one of the many holes around our yard. We moved a large container and there was a hole, in it was a pair of claws. We put the animal in a small jar an googled the facts to found out what it was.

Hi Stuart, Land Yabbies are a good challenge to try to keep as pets. Some species are threatened in Victoria so they would be better left in their natural environment. Other species are not protected and can be collected from your own backyard, make sure you check with the government before you collect. There are a few main factors that will make keeping these animals a challenge. Firstly – they live in a well formed burrow in muddy substrates – you would very rarely see them as it will be important to leave their burrow intact. You need to keep that moisture level quite well balanced between wet and saturated so they don’t drown or dry out. Second problem is the food that you feed them, in the wild they like to feed on rotting decaying matter that may be hard to offer – I would give vegies and the occasional worm a go as an alternative food source. Lastly and what I think may be very important is they live in quite cool climates and keeping them in a house that heats up over summer may be a bit too warm for them. Here at the museum we have some species of spiders that get too warm in the ambient temperatures so we solve the problem by housing them in a constant temperature cabinet maintained at around 16C. Best of luck with these land yabbies. What may be best is to enjoy this group of animals in their natural environment – head out at night time and see if you can spot them tending their burrows and feeding. By watching them in the wild it will give you good ideas on how you can go about keeping them as pets.

I live in Chirnside Park and there must be hundreds of them they make such a mess of my lawn. My daughter lives in Narre Warren and also has them, she has layed pavers and pebbles and they keep coming up in certain spots and putting mud all over the pavers. I would also like to know is there anyway of controlling them. They certainly aren't threatened around here.

Hi Emily, these small invertebrates usually remain deep in their burrows coming close to the surface at night to deposit soil from their diggings. You may be able to go out at night and see if you can collect a specimen. I would imagine that they will probably move back down their burrows quite quickly if disturbed so catching one may be difficult. Be warned that while they are relatively small their pincers are powerful and capable of delivering a painful pinch. We don't know whether food tied to a piece of string may coax them to the surface where you can see them but you may want to try it depending on how keen you are and how much patience you have.

Our lawn also has holes as described in this piece (including the mud chimneys!). I would like to catch one of these land crayfish to confirm that this is indeed what is digging these burrows. How would I do this? Thanks!!

Hi Paul - Whilst we can perform identifications, Museum Victoria does not specialise in invertebrate control. Our entomologist suggests you might wish to investigate any environmental conditions that would be encouraging the crayfish, such as overly damp ground, but other than that, we suggest you speak with your local council for suggestions. All the best!

I understand that these are threatened species but we have them on our property and they are causing damage to our foundations. I would like to be able to control this damage and do not want to kill them but would like to encourage them to move elsewhere. If anyone has any idea please let me know. I know some people poison them but this is an absolute last resort. I have tried filling in their burrows but they just build one next to it. Thanks

Hi Jimmy and thanks for your query. Museum Victoria is unable to provide qualified advice in regard to the structural foundations of your house. Perhaps you may be able to contact an engineering company, building association or gardening business for further advice.

We found one in Croydon in the back yard, we are going to keep it in a tank of its own as we have already ruined its home (not intentionally). They seem to be plentyful around here as there holes pop up widespread.

I've seen these "land crayfish" in northeast ohio and western pennsylvania. Maybe thats a known thing, but not many people I talk to know anything about them. They've gotta be all over the place around here if I've seen them in so many places.